The invention resides in a photosensitive composition for screen printing. Preferably, the composition of the invention comprises a polymer comprising a vinylpyridine monomer or polymer having a pyridinium salt character and a photoreactable constituent. The resulting stencil, once dried, exposed, cured, and subjected to alkaline treatment obtains enhanced solvent/water resistance but can be reclaimed using an acidic wash. In use, the stencil provides a screen/stencil assembly or blockout utility of high structural integrity through repeated use and screen printing images of high resolution and quality.

The invention relates to polymeric preparations that can be used in screen printing processes. Further, the invention relates to a film or a liquid polymeric composition that when used in combination with aqueous alkaline liquids, such as an alkaline ink, can form sharp long-lived stencil/screen assemblies used in screen printing operations. More particularly, the invention relates to polyvinylpyridine (or pyridinium) containing films that can be cast from aqueous solutions which, after imaging and in contact with an alkaline liquid such as a screen printing ink, at a pH greater than 7, forms screen stencils with increased or improved water resistance that can be used in screen printing processes. The composition of the invention can be reclaimed from the screen using an aqueous acidic reclaiming composition.
Images have been formed by screen printing processes for many years. In screen printing, an image is formed on a substrate by positioning a stencil comprising a given pattern in or on a finely divided mesh screen. An ink is then applied through the stencil/screen assembly onto the substrate resulting in a complementary image on the substrate. Such patterned stencils have been formed on screen constructions using a variety of techniques. Both photosensitive (negative and positive image) and non-photosensitive image forming processes have been used. The photosensitive materials used in making emulsion or film products can be solvent based or can be aqueous based. In many industries, including photostencil industries, the trend is away from solvent based materials to materials manufactured from or based on aqueous formulations. Many photosensitive film and liquid dispersions are now based on aqueous products. In a similar vein, both solvent based inks and solvent containing screen wash compositions have been used in screen printing operations. In response to demands of the market, vendors of screen printing materials have introduced water based inks. The use of water based or aqueous inks can cause images on stencils, made from water based films or aqueous emulsions, to swell or deteriorate reducing the effective lifetime of the stencil and image quality. Because these image layers formed from typically aqueous materials tend to interact with water based inks and swell, soften or otherwise deteriorate, a substantial need exists to improve the printing properties of materials derived from aqueous based systems for printing with water based inks.
We have found that the pH sensitivity of polymers having pendant units comprising a non-photosensitive nitrogen heterocycle, preferably a polymer comprising vinylpyridine (pyridinium), can be used to improve both photosensitive and non-photosensitive aqueous compositions and films, such as aqueous resist materials, blockout formulations and hand cut films, when used in screen printing with aqueous ink formulations. The screen printing stencil composition of the invention comprises a photosensitive polymer or photoresist material and a non-photosensitive polymer comprising pendant units comprising a nitrogen heterocycle such as a vinylpyridine and an aqueous vehicle or carrier. The invention can also be embodied in non-photosensitive compositions and methods.
Polymeric materials have been used in resist materials as both photosensitive and non-photosensitive components. Non-photosensitive components act as stabilizers, film forming agents, vehicles, pigments etc. A large variety of vinyl polymers take this role including polystyrenics, polyvinyl alcohols, polyacrylics, polyvinyl acetates; etc. In this regard pyridinium materials have also been used. Examples of photosensitive materials using pyridinium materials include the following. Leubner et al., U.S. Pat. No. 2,811,510, teach the use of light sensitive polymeric stilbazoles and salts thereof which are quaternized polyvinylpyridine materials having photopolymerizable unsaturated units. Takeda et al., U.S. Pat. No. 4,245,027, teach a light sensitive image recording material that uses a compound which on exposure to actinic radiation is capable of complexing a polyvinylpyridine material or a compound which releases a precursor capable of complexing polyvinylpyridine to form a pyridinium salt. The Takeda et al. material requires an activating exposure to appropriate wavelengths of light. Chiang et al., Journal of Organic Chemistry, Vol. X, pp. 21-25 (1945) teach the light sensitivity of stilbazole nuclei. Ichimura et al., Journal of Polymer Science: Polymer Chemistry Edition, Vol. 18, pp. 891-890 (1980), teach the reaction of the homopolymer of 2-chloroethyl vinyl ether and the copolymer of N-vinylpyrrolidone with stilbazole to form photosensitive polymers that can be used to immobilize enzymes. Borden, Canadian Patent No. 901,370, teaches photosensitive polymeric compositions containing vinyl styryl pyridinium materials insolubilized by the action of actinic radiation. Haas, U.S. Pat. No. 3,507,846, teaches methods for polymerizing vinylpyridine into polyvinylpyridine polymers. Yamaoka et al., U.S. Pat. No. 4,515,886, teach photosensitive materials useful as photoresists in the manufacture of semiconductors, transistors and other electrically active components in aqueous systems for photosensitive compositions. Day et al., U.S. Pat. No. 4,477,552, teach a use of a small amount of a non-photosensitive polyvinylpyridine (less than about 1 wt-%) as a stabilizer for water sensitive colloidal diazo-resin sensitizers. The pyridinium materials neither directly participate in the resist formation photoreactions nor provide any substantial properties to the stencil other than the stability of the diazo.
In a stencil or film, when in contact with acid, the pyridine polymer converts into a water soluble or dispersible pyridinium form. An opposite process can be easily performed by action of base. In contact with a base, the acid salt (quaternary) form of the polymer regenerates original polymer (in free amine form) that is inherently water insoluble. Such properties could be demonstrated with polyvinylpyridine (substituted or not in a homopolymer or copolymer form), quinolines, polyvinyl quinaldines, polyvinyl quinazolines and other polymers that have a nitrogen atom in a main chain or in a backbone.
The success of the use of the acid-base properties or pH solubility/sensitivity of the preferred non-photosensitive pyridinium materials in the resist to improve the image forming properties of the resist is a surprise. When contacted with acid, the pyridine nitrogen forms an amine salt. As shown below, the acid base reaction can be used to convert the polymer from a soluble pyridinium salt to a water insoluble free amine (pyridine) moiety. The insoluble pyridinium materials used at a concentration of greater than about 5 wt % hardens and improves the image.
The reaction of a sufficient proportion of the pyridine moieties to form the pyridinium form renders the polymer soluble or dispersible in aqueous media. When contacted with sufficient proportions of alkaline materials, the water soluble pyridinium salt is converted to the free amine form (pyridine) which is substantially water insoluble. We have found that the alkaline character of common water-based inks cooperates with the nitrogen heterocycle in the polymeric composition in the screen stencil to improve the finished stencil. In the preferred mode of the stencil composition, the polymer comprising repeating units with the nitrogen heterocycle pendant groups can have a degree of polymerization of about 50 to 100,000. The polyvinylpyridine can be a homopolymer having a molecular weight ranging from about 104 to 106. The polymer comprising vinylpyridine can be formulated with other vinyl polymers, photosensitive compounds or compositions, surfactants, co-solvents, dyes, etc. The polyvinylpyridine can also be used in blockout formulations without a photosensitive material. These materials can be used in forming hand cut stencils from sheet stock comprising the polymers of the invention. Such stencils are made by first cutting into a sheet of the materials of the invention an image as desired. The cut sheet is applied to a screen and then contacted with an alkaline ink in a printing operation. The alkaline ink improves the hardness and water resistance of the film/screen.
A method of using the stencil composition of the invention includes applying or coating the photosensitive stencil composition on a screen, drying the composition, exposing the stencil (selectively imagewise) composition to actinic energy, developing the image, optionally drying the image, treating the stencil with an alkaline solution (in blockout or printing operations) or treating a dried stencil with an aqueous, alkaline ink and printing a substrate. The used stencil can be reclaimed by treating the stencil material with an acidic reclaim composition.
We have found that a variety of the problems related to stencils, masks, and photoresists used in screen printing can be solved by compounding the stencil with a heterocyclic non-photosensitive nitrogen containing polymer such as a polyvinylpyridine. Using the pH sensitive solubility of such polymers comprising a nitrogen heterocycle or a pendant vinylpyridine, a mask or stencil can be hardened or made water resistant on a screen. A minimal proportion of ink used in the printing process can result in hardening the stencil containing the polymeric materials of the invention. The ink rapidly hardens the preferred pyridinium (soluble moiety) to pyridine (insoluble moiety) at the use concentrations of the material in the photoresist. The alkaline ink acts to insolubilize the polyvinylpyridine and to print. To make a previously imaged and developed stencil with increased water resistance which can be used in screen printing operations, the alkaline ink can be used. When operations are completed, the screen can be contacted with an acid (i.e, an acidic reclaiming composition) and the polyvinylpyridine stencil composition can be reclaimed.
The polyvinylpyridine used in the formulations of the invention is preferably in the form of a pyridine material wherein the heterocyclic nitrogen has been reacted with an acid to form a pyridinium salt. Such polymers are substantially water soluble or dispersible and can easily be compounded with other materials in manufacture of stencils or masks on screen. The compounded stencil materials have increased water resistance as the pH of the alkaline treatment (ink or other liquid materials in contact with the stencil) increases above about 7. These materials can be rendered useful in a medium of pH greater than 7. Preferably, the base is provided by a basic screen printing ink.
The water resistance of aqueous based photoresist materials can be improved using an aqueous polyvinylpyridine in a water soluble dispersible form, when treated with an alkaline ink. The alkaline ink further insolubilizes the imaged composition comprising the polyvinylpyridine material on the screen. The stencil image is made increasingly water resistant through the action of the base present in the ink. When the useful life of the screen/stencil assembly is at an end, the polymeric materials used in forming the image can be reclaimed by contacting the image with aqueous acidic reclaiming composition.
The invention can comprise an aqueous screen printing mask or stencil composition which can be insolubilized by the action of actinic light and having screen printing properties that can be further improved by a cooperation between an alkaline ink and a polymer with pendant units comprising a nitrogen heterocycle preferably a polyvinyl pyridinium composition, as well as methods of using the same, screens resulting from the use of this composition, and screen images resulting from the methods of the invention. Generally, the film of the invention or the aqueous stencil composition comprises a polymeric material such as a polyvinylpyridine constituent and a photosensitive material. The film or dispersion may also comprise a second vinyl polymer or copolymer, an acid source, and a photoreactive compound. The invention can also be used in a blockout composition or process or in a hand cut stencil. When used in blockout processes the polyvinylpyridine composition, in solution or suspension and optionally combined with other non-photosensitive components, can be applied to stencil flaws or other areas not covered by the stencil image. The applied material can be contacted with an alkaline material, insolubilizing the polyvinylpyridine in the blocked out areas. The blocked stencil can be used in standard printing operations.
The non-photosensitive polymer comprising repeating units comprising a pendant nitrogen heterocycle can be made from a monomer of the formula:
wherein the R1, R2 or R3 are independently a lower alkyl and A is a nitrogen heterocycle including an unsubstituted or substituted pyridine moiety, a quinoline moiety, a quinazoline moiety, a quinaldine moiety etc. The heterocycle substituents are non-photoreactive.
A. Polyvinylpyridine
The preferred heterocycle containing polymer comprises a polymer made of a vinylpyridine. Suitable polyvinylpyridine polymer compositions which are preferably employed in the present invention include polymers containing at least one repeating unit derived from a polymerizable monomer selected from the group consisting of the vinylpyridine polymeric or copolymeric materials of the general formulae (I, II or III) described below. More specifically suitable polyvinylpyridines include homopolymers as shown in the formulae; copolymers of at least two different polymerizable monomers selected from the group consisting of the vinylpyridine compounds and other compatible copolymerizable pyridine monomers; and copolymers of at least one polymerizable monomer selected from the group consisting of the vinylpyridine compounds represented by the general formulae (I, II or III) described below and at least one other polymerizable monomer. Suitable addition polyvinylpyridine compounds, (polymers or copolymers) which are used can be represented by the general Formulae (IV or V) below.
These polymers (Formulae I, II or III) are generally alkaline and insoluble in aqueous solutions at pH  greater than 7, and may be solubilized or dispersed in aqueous solution by a mild or strong, inorganic or organic acid. Examples of categories of acids that can be used include both Lewis acids and proton donor acids. Such acids can form a complex with the amine or can donate a proton to the amine group, such as the pyridine nitrogen forming a pyridinium (pyridine salt). The pyridine nitrogens can be fully or partially neutralized. Examples of suitable acids include phosphoric acid, acetic acid, sulfuric acid, hydrochloric acid, etc.
The reaction product is a water soluble or dispersible quaternary vinylpyridine polymer such as that shown in Formulae (IV, fully neutralized or V, partially neutralized).
The resulting polymer comprises either a fully neutralized polyvinylpyridine or a partially neutralized polyvinylpyridine, wherein n is 50 to 100,000, having an aromatic nitrogen with an amine salt character which may be referred to as a pyridinium salt, the salt anion being a chloride or sulfate, for example. To promote solubility, the acid neutralization is generally effective to neutralize at least about 30 wt-% of the polymer. As a result, neutralization may lead to a solution or dispersion of the polymer where the compound is completely or, only partially soluble.
While not preferred, the pyridine polymers useful in the invention may be substituted on the polymer backbone or on the aromatic nucleus. In such a case, non-photoactive substituent groups (R1, R2, R3, or R4) at each of the positions may independently comprise a hydrogen atom or a straight or a branched chain alkyl group containing 1 to 7 carbon atoms (e.g., a methyl group, an ethyl group, an n-propyl group, an isopropyl group, an n-butyl group, a t-butyl group, an n-heptyl group, etc.).
Specific examples of such substituents include a hydrogen atom, a methyl group, an ethyl group, an n-propyl group, an isopropyl group and an n-butyl group.
Preferred specific examples of vinylpyridine monomers include 4-vinylpyridine, 3-vinylpyridine, 2-vinylpyridine, 2-methyl-4-vinylpyridine, 2-ethyl-5-vinylpyridine, 3-methyl-5-vinylpyridine, 3-n-butyl-5-vinylpyridine, 2-ethyl-4-vinylpyridine 3-methyl-4-vinylpyridine, 3-isopropyl-4-vinylpyridine, 2-methyl-5-vinylpyridine, and the like. Generally, preferred polymers will have a molecular weight ranging preferably from about 104 to 106.
B. Copolymers
The screen printing stencil composition of the invention may comprise the vinylpyridine structures shown in Formula I through V. Alternatively, the screen printing stencil composition of the invention may comprise a copolymer of the structures shown in Formula I through V and one or more comonomers.
In the case of copolymers, the copolymer may be a copolymer of two or more of the above-described vinylpyridine monomers or the copolymer may be a copolymer of one or more of the above-described vinylpyridine monomers and one or more other addition polymerizable monomers capable of copolymerizing with the above-described vinylpyridine monomers. A broad range of different copolymerizable monomers can be used. There is no restriction on the copolymerization ratio between vinylpyridine in copolymers containing only vinylpyridine monomers but in copolymers with other copolymerizable addition polymerizable monomers the mole fraction of the vinylpyridine monomer units to the total monomer units in the resulting copolymer is preferably more than about 0.3. Further, the resulting copolymer must be insolubilized due to the interaction of the pyridine moiety with the aqueous alkaline ink.
Examples of suitable addition polymerizable monomers capable of copolymerizing with the vinylpyridine polymers of the general formulae (I through V) above which can be used include mono-olefin compounds such as ethylene, propylene, butene, etc.; diene compounds such as butadiene, isoprene, chloroprene, methoxybutadiene, cyclopentadiene, 1,3-cyclohexadiene, etc.; vinyl halide compounds such as vinyl chloride, vinyl bromide, vinyl fluoride, etc.; halopropene compounds such as 2-chloropropene, 1-chloropropene, 2-fluoropropene, etc.; vinyl ether compounds such as vinyl methyl ether, vinyl ethyl ether, vinyl n-propyl ether, vinyl isopropyl ether, vinyl n-butyl ether, vinyl isobutyl ether, vinyl tert-butyl ether, vinyl neopentyl ether, vinyl 2-methoxyethyl ether, vinyl 2-chloroethyl ether vinyl 2,2,2-trifluoroethyl ether, vinyl benzyl ether, etc.; styrene compounds such as styrene, xcex1-methylstyrene, 4-chlorostyrene, dichlorostyrene, 2,5-dimethoxystyrene, 4-methylstyrene, 4-ethylstyrene, etc.; aromatic vinyl compounds other than styrene, etc.; N-heterovinyl compounds other than the compounds represented by formulae (I) and (II) such as N-vinylcarbazole, N-vinylpyrrolidone, etc.; acrylic acid compounds such as acrylic acid, methacrylic acid, etc.; acrylic acid ester compounds such as methyl acrylate, ethyl acrylate, butyl acrylate, etc.; methacrylic acid esters such as methyl methacrylate, ethyl methacrylate, n-propyl methacrylate, n-butyl methacrylate, isobutyl, isobutyl methacrylate, n-hexyl methacrylate, 2-ethylbutyl methacrylate, n-lauryl hexyl methacrylate, 2-ethylbutyl methacrylate, n-lauryl methacrylate, 4-(tert-butyl)phenyl methacrylate, bornyl methacrylate, etc.; acrylonitrile compounds such as acrylonitrile, methacrylonitrile, etc.; acrylamide compounds such as acrylamide, N,N-dimethylacrylamide, N-(1,1-dimethyl-3-oxobutyl)acrylamide, etc., and the methacrylamides corresponding thereto; vinyl methyl ketone; methyl isopropenyl ketone; maleic anhydride; vinyl ester compounds such as vinyl acetate, vinyl chloroacetate, vinyl n-butyrate.
C. Aqueous Vehicle
Generally, the screen stencil composition of the invention is produced as an aqueous composition. The compositions of the invention can be made by dispersing or dissolving the components in water or a water blend. Preferably, the materials of the invention are made by dissolving or suspending the polyvinylpyridine polymer composition in an aqueous photoresist dispersion. The films of the invention can be made from such an aqueous material. For the purposes of this invention, the vehicle is the liquid continuous phase of the composition and can contain a major portion of water and other miscible co-solvents. The vehicle may also contain other conventional ingredients including dyes, wetting agents and may also comprise any number of other constituents. The aqueous vehicle is formulated to dry quickly and have a viscosity permitting ease of application. The polyvinyl polymer is suspended or emulsified in the aqueous phase. Generally, any liquid which will provide these functions without creating a volatile organic character in the composition may be used in accordance with the invention.
Various carriers include water, mono-, di-, and polyhydric alcohols such as methanol, ethanol, n-propanol and isopropanol, alkene and alkene glycols, and the like.
D. Photoreactive Compound
The stencil composition of the invention comprises a photosensitive compound to cure the stencil once it is placed on the screen. The preferred compound will be aqueous soluble and photoreactive when exposed to an actinic source of energy. The photosensitizing additives to be used in this invention may be low or high molecular weight substances.
Sensitizers commonly used in photopolymerizable resist compositions are monomers having photosensitive ethylenically unsaturated groups such as vinyl, acryloyl, methacryloyl, allyl, vinyl ether, acrylamide, or other groups or prepolymers thereof having an average degree of unsaturation of about 1 to 5. Examples of sensitizers having a single ethylenically unsaturated group include acrylamide, acrylic acid, methacrylic acid, methyl methacrylate, and methylol acrylamide. Preferred polyfunctional sensitizers have two or more photosensitive ethylenically unsaturated groups including sensitizers such as pentaerythritol triacrylate, pentaerythritol tetraacrylate, pentaerythritol trimethacrylate, pentaerythritol tetramethacrylate, 2,2,-dibromo methyl, 1,3-propane diacrylate, triallyl isocyanurate, N,Nxe2x80x2-methylene bis-acrylamide, and prepolymers thereof. The most preferred sensitizer comprises pentaerythritol triacrylate.
The composition of the present invention can further comprise a diazo resin complex photocross-linking agent. As the diazo resin, water-soluble diazo resins formed by condensing diazotization products of diphenylamines such as p-aminodiphenylamine, 4-amino-4xe2x80x2-methyldiphenylamine, 4-amino-4xe2x80x2-ethyldiphenylamine, 4-amino-4xe2x80x2-methoxydiphenylamine, 4-amine-4xe2x80x2-chlorodiphenylamine and 4-amino-4xe2x80x2-nitrodiphenylamine with aldehydes such as p-formaldehyde, acetaldehyde, propionaldehyde and n-butylaldehyde can be used. The complexes can be formed between the above-discussed condensation products and sulfuric acid salts, phosphoric acid salts and zinc chloride double salts. The photocross-linking agent can be used in an amount of up to 20 parts per 100 parts of the light-sensitive heterocyclic quaternary group-added polymer.
Polymerization reaction initiators suitable for use in the invention are those materials which will easily generate free radicals upon exposure to heat or ultraviolet radiation. Examples of these initiators include benzoin-alkyl ethers, Michler""s ketone, ditertiary butyl peroxide, dibenzothiazollyl-disulfide, dibromoacetophenone, anthraquinone, azobisisobutyronitrile, and the like. In a similar fashion the ethylenically unsaturated resists of this invention can contain optional functional compounds such as defoamers, surfactants, dyes, antioxidants, or other additives commonly used in this art.
Additional optional additives that can be used in the practice of this invention include surfactants used to increase the compatibility of the aqueous resist composition with the surface of the object and to promote an even coating. A defoamer can be used to insure that the layer of resist is free of small bubbles and other foamed species. A dye can be used to permit visualization of the position and approximate thickness of the resist composition. An antioxidant can be used for the preservation of the concentrations of the crosslinking activator.
The photoresist film comprising the photopolymer may be formed in any manner known to those skilled in the art including spraying, casting, reverse or roll coating, dipping, and doctor blading. Other methods of formation and photosensitive uses beyond those specifically disclosed herein will be recognized by the practitioner. These methods and uses of the invention are intended to be within the scope of the claims appended to the end of this specification.
There is no specific limitation for the amount of addition of these substances, but a preferable range is from about 10% to 50% by weight more preferably from about 10 wt-% to 30 wt-%, and most preferably from about 15 wt-% to 25 wt-%.
E. Vinyl Polymers
The aqueous photosensitive materials of the invention can contain a vinyl polymer in solution or dispersion form to aid in forming the images of the invention. Such vinyl polymers are film forming materials commonly used in aqueous solution or suspension.
In the case of copolymers, the copolymer may be a copolymer of two or more of the monomers disclosed below. There is no restriction on the copolymerization ratio between monomers. Further, the resulting copolymer must be soluble or dispersible in the aqueous resist.
Examples of suitable addition polymerizable monomers capable of copolymerizing with the vinylpyridine polymers of the general formulae (I through V) above which can be used include mono-olefin compounds such as ethylene, propylene, butene, etc.; diene compounds such as butadiene, isoprene, chloroprene, methoxybutadiene, cyclopentadiene, 1,3-cylcohexadiene, etc.; vinyl halide compounds such as vinyl chloride, vinyl bromide, vinyl fluoride, etc.; halopropene compounds such as 2-chloropropene, 1-chloropropene, 2-fluoropropene, etc.; vinyl ether compounds such as vinyl methyl ether, vinyl ethyl ether, vinyl n-propyl ether, vinyl isopropyl ether, vinyl n-butyl ether, vinyl isobutyl ether, vinyl tert-butyl ether, vinyl neopentyl ether vinyl 2-methoxyethyl ether, vinyl 2-chloroethyl ether vinyl 2,2,2-trifluoroethyl ether, vinyl benzyl ether, etc.; styrene compounds such as styrene, xcex1-methylstyrene, 4-chlorostyrene, dichlorostyrene, 2,5-dimethoxystyrene, 4-methylstyrene, 4-ethylstyrene, etc.; aromatic vinyl compounds other than styrene, etc.; N-heterovinyl compounds other than the compounds represented by formulae (I) and (II) such as N-vinylcarbazole, N-vinylpyrrolidone, N-vinylpyridine, etc.; acrylic acid compounds such as acrylic acid, methacrylic acid, etc.; acrylic acid ester compounds such as methyl acrylate, ethyl acrylate, butyl acrylate, etc.; methacrylic acid esters such as methyl methacrylate, ethyl methacrylate, n-propyl methacrylate, n-butyl methacrylate, isobutyl, isobutyl methacrylate, n-hexyl methacrylate, 2-ethylbutyl methacrylate, n-lauryl methacrylate, 4-(tert-butyl)phenyl methacrylate, bornyl methacrylate, etc.; acrylonitrile compounds such as acrylonitrile, methacrylonitrile, etc.; acrylamide compounds such as acrylamide, N,N-dimethylacrylamide, N-(1,1-dimethyl-3-oxobutyl)acrylamide, etc., and the methacrylamides corresponding thereto; vinyl methyl ketone; methyl isopropenyl ketone; maleic anhydride; vinyl ester compounds such as vinyl acetate, vinyl chloroacetate, vinyl n-butyrate.
F. Acids
For the purposes of this invention, any organic or inorganic acid can be used that promotes the solubility of the nitrogen heterocycle containing polymer. Any of a large number of sources of acidity may be used to lower the pH of the aqueous solution used to maintain the solubility of the pyridinium salt prior to, and during deposition as well as reclaim the stencil composition. Both a Lewis acid, an electron pair acceptor, or a proton donor acid can be used. For the purposes of this invention a proton donor acid can be represented by the formula H+Xxe2x88x92wherein H+ is an aqueous dissociable proton and Xxe2x88x92 is an anion. Such anions can include protonated anion such as H2PO4xe2x88x92, HSO4xe2x88x92, etc. Representative sources of acidity include inorganic and organic acids such as hydro- and hypo-chloric, and bromic acids, as well as, sulfuric acid, phosphoric acid, and nitrogen based acids among others. Organic acids useful in accordance with the invention include saturated and unsaturated aliphatic carboxylic acids including mono-, di-, and polycarboxylic acids, acetic acid, fumaric acid, propionic acid, citric acid, malic acid, lactic acid and mixtures thereof.
Generally, to ensure the solubility of the pyridinium salt the pH of the stencil composition as well as the reclaim solution should be less than about 8, and preferably from about 2 to 7.
The unique solubility properties of polyvinylpyridine can be used in blockout processes and products. The blockout process involves forming a coating on a screen in a non-photosensitive process. Such processes are often used to repair flaws in images and to form borders or other large blockout areas required to successfully form an image on a substrate. The blockout processes are commonly practiced by applying a material containing a polymeric film forming material to the screen and drying the polymeric material into an intact film. We have found that the polyvinylpyridine materials of the invention can be used in such blockout materials to increase the water resistance of blockout products. Commonly a blockout product can comprise in a water base, a film forming polymer, a polyvinylpyridinium material, and optionally, acid if needed to form this pyridinium acid salt. A blend of polymeric materials can be used in the blockout material to optimize the film forming properties. Blockout materials on the screen can be reclaimed using an aqueous reclaiming acidic composition in the same reclaiming process as the image formed from the photosensitive materials. Any of the vinyl polymers having nitrogen heterocycle side groups can be used in forming the blockout products of the invention. The polymeric film forming compositions are all well known materials and are discussed above in the vinyl polymers.
In accordance with the invention, the stencil may be used with any number of aqueous alkaline ink compositions. Preferred ink compositions include those which are stable in an aqueous, alkaline median or carrier so as to not solubilize or otherwise detract from the developed stencil composition.
Useful inks include the Aquasoft 400 LF ink product series made by PANTONE, the SINVAQUA ink by SUMMIT, the 2500, 2700, 8500 and 9500 ink series sold by NA2-DAR, and other well known aqueous alkaline inks. The basicity of the inks causes the pyridine moiety of become insoluble. In blockout applications the polymer can be contacted with an alkaline solution to render the polymer insoluble. The solution can be made in any suitable aqueous liquid, water being preferred. The useful alkaline materials include any material that can produce an alkaline pH in the aqueous liquid. Conventional weak and strong bases can be used. Examples of suitable bases include inorganic bases such as NaOH, KOH, NaCO3, NaHCO3, NH4OH, and organic bases such as monoethanol amine, diethanol amine, etc.
The stencil composition of the invention may be used in any number of applications based upon screen printing. Non limiting examples include the following process.
Generally, screen stencils can be prepared by either applying an aqueous emulsion, containing a photosensitive material and the heterocyclic group containing polymer or polyvinylpyridine, to a screen mesh. Alternatively, a stencil can be made by applying a photoreactive or non-photoreactive water soluble film to the screen mesh. Non-photoreactive films can be imaged in a number of ways including hand cutting, hand painting, etc. The film or emulsion can be dried if necessary prior to exposure. The stencil can be exposed to actinic radiation using either a photopositive or photonegative method to transfer the image. The portion of the stencil to be removed (depending on the photopositive or photonegative nature of the exposure process) is developed or washed out with a waterstream until the undesirable portion of the stencil is completely removed. The image stencil is then dried and then applied in printing operations using preferably an alkaline ink. When contacted with an alkaline ink, the materials made from the aqueous emulsion obtained increase resistance to the effects of water due to the presence of the heterocyclic containing polymer or the polyvinylpyridine material. In an alternative preparatory method, after the film is developed or washed out with a water spray, the screen, either wet or dry, can be treated with a basic aqueous solution to further insolubilize the stencil prior to printing operations. The basic aqueous solution can be applied to either a wet or dry screen. However, preferably the aqueous alkaline solution is applied directly to a wet screen immediately after development. The non-photosensitive heterocycle containing polymers or polyvinylpyridine are more easily converted into an insoluble form when exposed to the alkaline solution in an aqueous medium. The alkaline aqueous solution is allowed to soak into the screen for a period of time. The solution may be applied either by spraying the solution directly on the screen or by the application of some material directly onto the screen by wetting, blotting, dipping or immersing the screen into a volume of the alkaline aqueous solution. After a period of time sufficient to ensure that the non-photosensitive polymers are sufficiently converted into the free pyridine form, the alkaline aqueous material can be washed from the screen with a water rinse. The stencil can be dried and can be printed immediately with an alkaline water based ink.

Screen printing stencil composition with improved water resistance


A cutting and stapling device for use as an attachment to an electromechanical device driver comprises an upper jaw and a lower jaw which separate and close against one another in a continuously parallel alignment. The upper jaw includes a series of staple guides corresponding to one or more staples in a removable staple tray disposed within a lower jaw, whereby a blade and wedge having a threaded bore travel upon a matching threaded shaft in a channel disposed in the lower jaw below the staple tray, such that rotation of the threaded shaft causes movement of the wedge through the channel while a sloped surface of the wedge contacts the staples to push the staples against the staples guides, closing the staples.

1. Field of the Invention
The present invention relates generally to an attachment for an electromechanical device for use with anastomosing, stapling, and resecting surgical tools, and more specifically to a stapling and resecting device which can be attached to and serve as an extension of an electromechanical device driver, and most specifically to the expanding parallel jaws and the mechanisms thereof.
2. Description of the Prior Art
Upon identification of cancerous and other anomalous tissue in the gastrointestinal tract, surgical intervention is often prescribed. The field of cancer surgery, and more specifically, the surgical procedure by which a section of the gastrointestinal tract which includes cancerous tissue is resected, includes a number of uniquely designed instruments. In combination with a description of the present instrumentation and their functions, a description of the state of the art in this surgical procedure shall also be provided.
The first question which must be answered when determining how to treat gastrointestinal tract cancer relates to the specific location of the cancerous tissue. This is very important insofar as the instruments which are provided in the present art have limitations relating to how far they may be inserted into the gastrointestinal tract. If the cancerous tissue is too far up or down the gastrointestinal tract, then the standard instrumentation provided is unusable, thus requiring special accommodations. These accommodations generally increase the risk of contamination of the surrounding tissues with bowel contents, increase the length of the surgery and the corresponding need for anesthesia, and eliminate the benefits of precise anastomosing and stapling which comes from utilizing a mechanized device.
More specifically, in the event that the cancerous tissue is located at a position in the colon which is accessible by the present instrumentation, the patient""s abdomen is initially opened to expose the bowel. The surgeon then cuts the tube of the colon on either side of the cancerous tissue, while simultaneously stapling closed the two open ends of the bowel (a distal end which is directed toward the anus, and the proximal end which is closest to the lower intestine). This temporary closure is performed in order to minimize contamination. The linear cutter and stapling instrument which is used in the prior art is provided in a perspective view in FIG. 1.
More particularly, this temporary closure is achieved when the colon is placed between the scissoring elements at the tip of the linear cutter and stapling instrument. By squeezing the trigger in the handle of the device, the surgeon causes the scissoring elements to come together. A second trigger (or a secondary action of the same trigger) is then actuated to drive a series of staples and a cutting blade through the clamped end of the colon, thereby closing and transecting the ends.
After the sealing of the two exposed distal and proximal ends, the surgeon creates a small opening in the proximal end of the bowel and inserts the removable anvil portion of an anastomosing and stapling instrument. This step, as well as those of the remainder of the surgical procedure, are related to the functioning of this surgical instrument which is provided in a perspective view in FIG. 2. More particularly, the surgeon begins by taking the instrument and manually turning the dial at the base of the handle which causes the anvil head at the opposite end to advance forward. The surgeon continues to turn the dial until the anvil head advances to its most extreme extended position. This manual turning requires nearly thirty full rotations. Once fully extended, the anvil head of the instrument is decoupled therefrom and is inserted into the exposed proximal end such that the coupling post extends outwardly therethrough. As described above, this proximal end is then stapled closed. The extending shaft of the anastomosing,and stapling instrument is then inserted and advanced into the lower colon, transanally, until the coupling stem thereof extends through the stapled distal end. The surgeon then joins the coupling ends of the anvil and shaft together and begins to manually rotate the dial in the handle again, this time bringing the anvil head closer to the tip of the shaft.
Once the anvil head and shaft are brought close together, after the surgeon has manually rotated the dial another thirty times, a grip-style trigger in the handle is manually actuated. This actuation causes a circular blade to advance axially out from the tip of the shaft, and into contact with the opposing face of the anvil. The blade cuts through the stapled-closed ends of the proximal and distal ends of the colon, thereby also cutting a new pair of ends of the proximal and distal portions of the colon. The tissue which has been severed is held in an interior volume at the end of the shaft.
In lock step with the cutting, the freshly opened ends are joined together by a series of staples which are advanced through holes in the perimeter of the tip of the shaft (being pressed against and closed by the opposing face of the anvil). The coupled shaft and anvil are then withdrawn from the patient.
More particularly with respect to the structural features of the linear stapling instrument of the prior art which is provided in FIG. 1, the device comprises a pistol grip-styled structure having an elongate shaft and distal portion. The distal portion includes a pair of scissors-styled gripping elements which clamp the open ends of the colon closed. In fact only one of the two scissors-styled gripping elements, the anvil portion, moves (pivots) relative to overall structure; the other remains fixed. The actuation of this scissoring means (the pivoting of the anvil portion) is controlled by means of a grip trigger maintained in the handle. A number of different means have been disclosed for holding the tips of the scissoring arms closed, including snaps, clips, collars, et al.
In addition to the scissoring means, the distal portion also includes a stapling mechanism. The non-moving element of the scissoring mechanism includes a staple cartridge receiving region and a mechanism for driving the staples up through the clamped end of the colon, against the anvil portion, thereby sealing the previously opened end. The scissoring elements may be integrally formed with the shaft, or may be detachable such that various scissoring and stapling elements may be interchangeable.
More particularly with respect to the structural features of the anastomosing and stapling instrument of the prior art which is provided in FIG. 2, the device comprises an anvil portion, a staple, blade and reservoir portion, a shaft portion, and a handle portion. The anvil portion, which is selectively removable from the tip of the shaft, is bullet shaped, having a blunt nosed top portion, a flat cutting support surface on the bottom, and a coupling post extending axially from the bottom surface.
The staple, blade, and reservoir portion (SBR portion) of the instrument is provided at the distal end of the instrument, and includes a selectively advanceable and retractable coupling stem for selectively receiving thereon the anvil portion. This action of the coupling stem is provided by a screw threaded shaft and worming mechanism mounted in the handle (described more fully below). The SBR portion is cylindrical in shape, forming a housing which has a hollow interior. It is this hollow interior which forms the reservoir. The blade is similarly cylindrical, and seats in the inside of the housing, against the inner wall thereof. The blade is selectively advanceable axially outward from the housing, in accordance with actuation of a trigger mechanism of the handle (again, described more fully below). On the axially outward facing surface of the cylindrical wall of the housing are a series of staple ports, through which the staples of the device are discharged. The same actuation which drives the blade forward similarly drivel a series of staple drivers forward within the cylindrical walls. More accurately, the staple driver is a cylindrical component which has a series of protuberances on the axial end thereof, the protuberances being positioned in accordance with the distribution of staples and holes. The staples, prior to being discharged, are mounted in the holes; and they are advanced through the holes by the action of the staple driver and the protuberances thereof.
The shaft portion of the instrument is a simple rigid extended structure which is intended as a sheath for a pair of elongate rods. The first rod is coupled to the worming mechanism introduced above, and described more fully below with respect to the handle portion, and is the means by which the anvil portion and the coupling stem of the SBR portion are selectively advanced and retracted. The second rod is coupled to the trigger of the handle at one end (also introduced above, and described more fully below) and to the blade and staple driver at the other end. The sheath protects the patient and the instrument when it is advanced into the colon transanally. The nature of the actuation mechanisms however, requires that the shaft be rigid. This rigidity limits the length of the shaft; and combination, i.e. the length and rigidity of the instrument, these features limit the sections of the colon which may be treated using this device.
The handle of this instrument of the prior art comprises a pistol grip styled structure having a turning dial at the butt (i.e. the end opposing the junction of the shaft portion which the handle) and a finger actuated trigger. The trigger includes a safety mechanism which physically prevents actuation unless moved out of the interference position. The turning dial is actionably coupled to a worming mechanism which is used to advance the first rod of the shaft portion (thereby advancing the coupling stem and the anvil). The trigger functions as a basic lever to push the second rod forward within the shaft, thereby advancing the blade and staple driver.
As with many such devices of the prior art, all of these devices are considered fully disposable, and are, in fact, thrown away after a single use. They are complicated devices, having multiple moving parts, requiring substantial structural integrity and, therefore, expense in manufacturing. The fact that they are used only once, and no part can be used again render the use of such devices expensive and wasteful of resources.
In addition to this failure, as can be readily observed from the preceding descriptions, the prior art devices suffer from numerous other limitations which would be desirable to overcome. These include the rigid and limited length shaft of the devices, as well as the requirement that the surgeon manually actuate all of the features and functions.
Therefore, it is a principal object of the present invention to provide an instrument for resecting and stapling gastrointestinal tissue during colon surgery, which reduces the waste of resources by permitting use as an attachment to an electromechanical device driver.
It is further an object of the present invention to provide an instrument assembly which reduces the requirements for the surgeon to manually actuate different components and mechanisms.
It is further an object of the present invention to provide a resecting and stapling mechanism that can be integrated with other electromechanical devices into an attachment for use with an electromechanical device driver.
Other objects of the present invention shall be recognized in accordance with the description thereof provided hereinbelow, and in the Detailed Description of the Preferred Embodiment in conjunction with the remaining Figures.
The preceding objects of the invention are provided by virtue of an electromechanical resecting and stapling attachment which is coupleable to and remotely actuateable by an electromechanical device driver. In particular, the attachment includes a pair of linearly spreading jaws for clamping the selected section of gastrointestinal tissue therebetween, said jaws expanding and closing in a parallel disposition. More particularly, the linear clamping mechanism of the attachment is used to first clamp the section of colon, and then to hold the colon in place as a blade extends along a track in the lower jaw of the clamping attachment to cut the section of bowel, and then drives a series of staples through the two opened ends so that the contents of the bowel are not permitted to empty into the surrounding region of the abdomen. This attachment, and others necessary to perform the remainder of the surgery, is coupled to an electromechanical driver which is described more fully hereinbelow.
More particularly, with respect to the electromechanical driver, the driver has a handle and a flexible drive shaft. The handle has a pistol grip-styled design, having a pair of finger triggers which are independently coupled to separate motors which each turn separate flexible drive shafts (described more fully, hereinbelow). The motors are each dual direction motors, and are coupled to a manual drive switch mounted to the top of the handle, by which the user can selectively alter the turning direction of each motor. This dual direction capacity may be most simply achieved by selecting motors which turn in a direction corresponding to the direction of current, and actuation of the drive switches alters the direction of the current accordingly. In this example, the power source supplying the motors must be a direct current source, such as a battery pack (and most desirably, a rechargeable battery pack). In the event that the device should be useable with an alternating current, either a transformer can be included, or a more sophisticated intermediate gearing assembly may be provided. In conjunction with the present description, the embodiments of the present invention which will be described utilize a rechargeable battery pack providing a direct current.
In addition to the motor components, the handle further includes several other features, including: (1) an remote status indicator; (2) a shaft steering means; and (3) at least one additional electrical supply. First, the remote status indicator may comprise an LCD (or similar read out device) by which the user may gain knowledge of the position of components (for example whether a clamping element is in the proper position prior to the driving of the staples). Second, the handle also includes a manually actuateable steering means, for example, a joystick or track ball, for directing the movement of the flexible shaft (by means of guidewires implanted in the shaft portion described more fully hereinbelow). Finally, the handle may include an additional electrical power supply and an on off switch for selectively supplying electrical power to the attachments.
More particularly, with respect to the flexible shaft, the shaft comprises a tubular sheath, preferably formed of a simple elastomeric material which is tissue compatible and which is sterilizable (i.e. is sufficiently rugged to withstand an autoclave). Various lengths of this shaft may be provided in conjunction with the present invention. In this case, the flexible shaft and the handle portions should be separable. If separable, the interface between the proximal end of the shaft and the distal end of the handle should include a coupling means for the drive components. Specifically regarding the drive components of the shaft, within the elastomeric sheath are a pair of smaller fixed tubes which each contain a flexible drive shaft which is capable of rotating within the tube. The flexible drive shaft, itself, simply must be capable of translating a torque from the motor in the handle to the distal end of the shaft, while still being flexible enough to be bent, angled, curved, etc. as the surgeon deems necessary to xe2x80x9csnakexe2x80x9d through the bowel of the patient. For example, the drive shafts may comprise a woven steel fiber cable. It shall be recognized that other drive shafts may be suitable for this purpose. In order for the distal end of the drive shaft to couple with an attachment, such as the clamping and stapling device of the present invention (as described more fully below), however, the distal tips of the drive shafts must have a conformation which permits the continued translation of torque. For example, the distal tips of the drive shafts may be hexagonal, thereby fitting into a hexagonal recess in the coupling interface of the attachment. As suggested above, in conjunction with the manually actuateable steering means mounted to the handle, the sheath further includes at least two guidewires which are flexible, but are coupled to the inner surface of the sheath near the distal end thereof. The guidewires may be axially translated relative to one another by actuation of the steering means, which action causes the sheath to bend and curve accordingly. Also, as suggested above, in conjunction with the LCD indicator of the handle, the shaft further contains an electrical lead for coupling to the attachments. This electrical lead channels a signal from the attachment to the handle for indicating the status of the attachment (for example, whether a clamping function is holding). Similarly, a second electrical lead may be provided to supply power to separate aspects of the attachment if so required (for example, as will be described more fully with respect to linear resecting and stapling attachment, the use of selectively engageable electromagnetic seal for ensuring continued clamping through the stapling process may be provided and require power selectively provided from the handle""s power supply).
More particularly, with respect to the linear resecting, clamping, and stapling attachment which is the specific subject of this invention, the attachment is fitted with two drive extensions, which in operation function as extensions of the flexible drive shafts of the electromechanical driver. That is, when the attachment is mated to the electromechanical driver, the drive extensions are in mechanical communication with the flexible drive shafts such that the activation of the drive shaft motors activates the drive extensions within the linear clamping, cutting and stapling attachment. The first drive extension enables the parallel spreading and closing of the jaws of the device, which form a linear clamping mechanism, while the second drive extension enables a cutting and stapling mechanism. More particularly, the linear clamping mechanism comprises a separating jaw system whereby an upper jaw is raised to permit the bowel tissue to be placed therebetween, and subsequently the jaws are closed to meet to effect a clamping. In a first embodiment, the first drive extension engages a pair of threaded vertical shafts which raise or lower the upper jaw depending on the turning direction of the corresponding motor in the electromechanical driver. In a second embodiment, the first drive extension includes only a single angled gearing mechanism mounted at the end of the horizontally rotating shaft (which is coupled to one of the turning shafts of the electromagnetic driver). This gearing mechanism causes the vertically rotation of a threaded shaft on which the upper jaw is separately munted. In both embodiments, when the jaws are closed, a pair of sensor electrodes disposed on the jaws come into contact and thereby complete a sensor circuit which alerts the surgeon that it is safe or appropriate to activate the resecting and stapling mechanism and/or automatically activates the resecting and stapling mechanism.
In each of these embodiments, the second driver causes a blade to slide along a track in the lower jaw, which blade cuts the bowel briefly leaving two open ends. Nearly simultaneous with the cutting, a stapling mechanism drives a series of staples upwardly through opening in the lower jaw, toward the upper jaw, through the open ends, thereby closing the bowel segments. This stapling action happens nearly simultaneous with the cutting in part because the blade is contiguous with a stapling mechanism of the present invention.
This stapling mechanism begins with a replaceable tray of open staples which is set within the lower jaw, the tray having two rows of staples separated along the long axis of the jaw so that the blade may track between the rows. The opposing upper jaw face includes a set of corresponding staple guides, such that when the linear clamping mechanism is in a closed position, the open staples immediately oppose the corresponding staple guides. This mechanism comprises a wedge pushing system whereby once the linear clamping mechanism is in a closed position, the blade and a wedge ride along together in a channel below the tray of open staples, and the staples are pushed up toward the staple guides, through the bowel. More particularly, as the wedge moves through the channel, a sloping surface of the wedge pushes the open staples against the corresponding staple guides, thereby closing the staples. After the staples have been closed, the wedge is pulled back through the channel. It is the first drive mechanism which lifts the jaws apart in parallel; and it is the second drive mechanism which pushes or pulls the wedge and blade mechanism through the channel. The direction of the first and second mechanisms is related solely to the remote operation of the driver, and the corresponding turning direction of the shafts, of the electromechanical driver.

Expanding parallel jaw device for use with an electromechanical driver device


Temporary, disposable glare shields made of thin flexible tinted plastic film, consisting of a set of two for left side and right side of eyeglasses, self-adhered to eyeglass outer surfaces, extending beyond frame perimeters and around both temporal sides thereby completely shielding all adjacent areas surrounding eyes from potential harmful sunlight UV and other components injurious to sight. In addition, such glare shields provide protection against harmful airborne hazards, strong wind, insects, pollution, contaminants and toxins that may otherwise impact eyes. Said glare shields are a size and shape that substantially fit all sizes and shapes of eyeglasses. They may also be worn directly on the face to cover eyes without eyeglasses, or be worn in this latter way with eyeglasses worn over said glare shields thus providing the sealed peripheral protection of glare shields and the visual improvement of prescription eyeglasses. A convenient pocket-size stowage folder is provided with each set of glare shields that gives instructions for use and may be used to store glare shields after use when and if needed again.

This present invention relates to improved temporary glare shields for eyeglasses and the like, and more particularly to glare shields in the form of inexpensive, disposable, lightweight thin plastic film having a shape and size that fits all shapes and sizes of eyeglasses and the like. This invention is self-adhered to eyeglasses and the like, and contains properties of tint that filter harmful UV and infrared rays, and provides complete peripheral protection from all potential sources of harmful sunlight properties, glare, airborne hazards, insects, contaminants and toxins. It may also be adhered directly to the face to protect eyes of persons not wearing eyeglasses.
A variety of arrangements exist that convert eyeglasses into sunglasses. As a result of my search of past United States Patents for relevant prior inventions the following patents have been disclosed:
Of the many attempts made to convert existing eyeglasses into sunglasses, all fall short in providing complete, low-cost, practical, and convenient temporary sun shield protection, particularly in those areas of peripheral vision above and below eyeglass frames, as well as at the temporal sides. Some efforts disclose special attempts to remedy certain potential visual problems present in the workplace or resulting in prolonged computer use. One attempt has to do with half-lenses that is inadequate when applied to other lenses. And, in other cases, non-transparent xe2x80x9cside-blindersxe2x80x9d are employed to shield bright light, airborne objects and other contaminants. In many such efforts temporary shields are used that only protect the limited area of host eyeglass lenses, allowing other surrounding regions to be exposed to the aforementioned hazards. And, in many cases, these efforts offer impractical solutions that are unaesthetic and bulky, and prove to be highly inconvenient.
For example, U.S. Pat. No. 111,494 to E. K. Madan on Sep. 27, 1938 discloses a design for sunglasses that is permanently attached to a spectacle frame, having front and side shade members. The disadvantage with this Madan invention is that it adds a disproportionate amount of weight to the front of the spectacles and would likely cause them to slide down the nose of the wearer. This potential problem would require frequent adjustment to maintain the proper positioning of spectacles on the face of wearers. The added device is permanently attached and cannot be conveniently removed when not needed. This Madan invention appears to be costly and is obviously not disposable. Although this devise shields areas in the front and sides, there are certain areas where sunlight will impact eyesight from above and below the frames. When assembled, this device cannot be stored in a conventional eyeglass case.
Another example, U.S. Pat. No. 2,388,626 to E. I. Wilson on Nov. 6, 1945 discloses an eyeglass shield in which the shield members are attached to the top of spectacle frames by a metallic hinge that allows adjustment to any angle or tilt. This Wilson invention is described as being composed of flexible sheet material, transparent, opaque or translucent and in another instant it is described as colored transparent material that shields the wearer from undesirable light rays.
Significant differences exist between this Wilson invention and my invention. For example, the Wilson sunshield is not a temporary device, and is not disposable because of its permanent attachment to eyeglass lenses. The added cost of this permanent attachment by itself makes this device not disposable when temporarily used as a sunshade.
In addition, considerable weight is added to the front of host eyeglasses that undoubtedly would cause this assembled device to slide down the nose of wearers and require frequent adjustment to maintain its proper position. The present invention does not create disproportionate weight to be added to the front of eyeglasses.
Another example, U.S. Pat. No. 2,511,329 to E. Craig on Jun. 13, 1950 discloses a lens shield consisting of thin flexible transparent material that is stuck to a spectacle lens to reduce glare and undesirable rays of the sun. It is adhered to eyeglass lens by an adhesive on one side of said material so that it conforms to the shape of the lens. Craig""s disclosure states that this shield may be removed when not needed and carried in a packet with other shields to be used again.
A tab is described that is positioned on each shield to single-out each layer of shield in the packet. But, the likelihood of these shields sticking together exists, as the adhesive needed for each shield within the packet has no differentiation to identify the top shield being removed from others beneath it in the packet. This creates a potential problem of lifting several shields from the top of the stack when only one is needed, even though the top tab is grasped,
And, since left and right eyeglass lenses are rarely the same shape, and are instead a mirrored image of each other, two such packets are required. One of these will contain left side shields and the other will contain right side shields. A potential problem of left and right shields becoming intermingled exists.
It should be noted that the present invention provides left and right side glare shields that are individually stowed in a handy pocketsize folder comprised of a set of two. There is never a problem of several glare shields sticking together. These are a shape and size that substantially fit all shapes and sizes of eyeglasses.
Yet another disadvantage with the Craig invention exists with the likelihood of glare entering eyesight from above and below eyeglass frames in the front as well as at the side temporal areas. The present invention provides complete glare protection above and below eyeglass frames and without a breach continues this protection at the sides around each temporal area.
Another example, U.S. Pat. No. 2,714,717 to A. D. Allman on Aug. 9, 1955 discloses a glare shield and eye shade for spectacles that are clipped on to eyeglasses that contain a hinge assembly that allows them to be raised or lowered when shielding glare. The Allman invention claims use of a pair of spaced hinges and an attachment using two clip-on hooks as a means of attachment to the lens rims. A disadvantage can be identified with this means since all shapes and sizes of eyeglasses will not fit the requirements to use this device, and use is limited to only those eyeglasses having a lens rim of the proper size required.
A further disadvantage is found in the shape of the Allman eye shades, as they do not extend above and below the eyeglass illustrated, as well as not providing protection at both temporal sides.
Another example, U.S. Pat. No. 2,759,394 to D. L. Evans on Aug. 21, 1956 discloses a glare shield for spectacle lenses in the form of a sheet of selectively transparent material that is applied to a spectacle lens by means of pressure sensitive adhesive. In doing so, the optical clarity of the lens is said to be substantially unaffected. Another claim is made that this is a type of shield that only a minimum number of different shapes and sizes are required for fitting the wide variety of shapes and sizes of eyeglasses currently in use. This claim gives rise to an obvious problem that is illustrated in FIG. 1 through FIG. 3 of the Evans"" drawings. It shows specific shapes and sizes of glare shields fitted snuggly within two spectacle frames, which should not be considered to be typical of the range of varied shapes and sizes in use. It is highly unlikely that such illustrated examples given can support the claim that only a minimum number of shapes and sizes are required to meet this vast marketing claim.
In addition, Evan""s states in his disclosure, xe2x80x9cIf the shield of my invention is made of cellulose acetate or any material moldable when heated, any ordinary forming technique may be employed to mold it into the curved-convex shape desired.xe2x80x9d He further discloses, xe2x80x9ca sheet of cellulose acetate may be heated to its softening temperature, which may be above boiling point of water for example. This stretched down over a convex mold having approximately a spherical curvature slightly greater than the curvature of the lens with which it is to be used.xe2x80x9d
There are a number of problems in these statements that someone having knowledge of plastic materials and molding of plastics can recognize. For example, Evans suggests use of thermoplastic material, the kind that may be molded again and again if heated, rather than the thermosetting plastics, the kind that cannot be molded again when heated. His use of a thermoplastic would create a problem if his sunshields were subjected to the heat of direct sunlight. They would become moldable plastic again, and tend to sag and assume an undesirable shape.
Secondly, there is no advantageous reason to construct glare shields having a xe2x80x9cspherical curvature slightly greater than the curvature of the lens.xe2x80x9d In fact, his molding method will create a small space or pocket between the shield and lens, which would be prone to accumulate moisture through the process of condensation when humid ambient conditions are present.
And, further, users of these glare shields must prepare them so they fit a specifically required shape and size host eyeglasses. This is a highly inconvenient requirement that likely would be avoided by those needing sunglasses.
Another example, U.S. Pat. No. 3,033,359 to S. N. Mercer on May 8, 1962 discloses a disposable less shield made of tinted transparent plastic that adheres to eyeglass lenses by electrostatic attraction. It distinguishes itself from others by featuring this electrostatic method of attachment rather than clip-on devices and other adhesive methods. It is claimed that self-adhesive methods of attachment cause residue to remain on the lenses and attract dust and other foreign matter. It is also claimed that glare shields using adhesives are xe2x80x9cdifficult to package and handle, and are tricky to place properly on the eyeglass lens.xe2x80x9d And, it is claimed that use of self-adhesives add to the cost of glare shields.
But, these negative claims are not credible, as self adhesive applications have been perfected in recent years that do not leave any residue on a host surface, and these applications are well established as a preferred method for a wide range of products, namely postage stamps. The small cost of using self-adhesives is far outweighed by the savings realized by this preferred method.
Further disclosed is a packaging method designed to hold a number of these Mercer lens shields, which is illustrated as a xe2x80x9cmatch bookxe2x80x9d type container. And, a lens cleaning tissue is supplied with this container which serves also as a tissue that is used to smooth wrinkles of the thin shield when it is applied to eyeglass lenses. These procedures can hardly be considered convenient, and must be performed whenever the Mercer lens shields are applied. It can be said that a working surface of some kind is required when placing these shields on to eyeglass lenses, which may not be available at times when outdoor bright sunlight is to be avoided.
In addition, this Mercer device does not prevent glare from entering eyesight from above and below eyeglass frames in frontal areas and at both peripheral areas at the side temporal regions.
Although this Mercer disclosure expresses the need for an economical and disposable eyeglass shield for public use that is low cost and can occupy little space in a pocket or handbag, thereby making it convenient for many situations, it falls short in meeting all of these requirements.
Another example, U.S. Pat. No. 3,171,134 to D. J. Kennedy on Mar. 2, 1965 discloses unitary sun shields for eyeglasses that claim to be detachable. It also claims to provide maximum protection against sun glare by extending protection below the frames in the front and around at both side temporal areas. This unitary device is positioned on the inner side of eyeglasses between the lenses and eyes of wearer and is snapped into this position at the top of eyeglass frames. Although this Kennedy invention protects a greater area of eyesight than most other related art, it fails to shield eyesight above eyeglass frames as illustrated in drawings FIG. 5, showing an aperture between No. 28 and No. 12.
In addition, this snap-on device is not disposable and is obviously more costly than my present invention. It should also be noted that the Kennedy invention requires eyeglass frames that accept the specifically shaped snap-on feature, and if the eyeglass frame is too large it cannot be engaged, and if too small the sunshield will be loose and likely fall off.
Another example, U.S. Pat. No. Des. 208,069 to S. Boxer on Jul. 11, 1967 disclose the design of a pair of clip-on sunglasses. This design patent shows a method of attachment using two clips that appear to be metallic that fit over eyeglass frames near the bridge of the nose. Two hinges are located on both sides so that they hold extensions of similar shield material in position along the temporal sides at right angles to the front shields. Since this is said to be an ornamental design patent, no disclosure is made of its function. But, from the limited drawings given this design seems not to be disposable, and is comparatively costly. No disclosure is made regarding tinting of the material used for shields, and any comment regarding sun-shielding capacity would require assumptions that may or may not be true.
This Boxer design would not fit all shapes and sizes of eyeglasses, limiting its use to those that fit this clip-on feature, as well as that distance from hinge to hinge between each side.
Another example, U.S. Pat. No. 4,217,037 to J. H. Lemelson on Aug. 12, 1980 discloses eyeglass shields that are used by those wearing half-lens eyeglasses. These shields extend above half-lenses in the front only, and provide no glare protection at the sides. Additional requirements of many shapes and sizes of half-lens eyeglasses impose severe restrictions to the locations of attachment means, which must be molded during manufacture of these shields. There is very little accommodation for the many sizes and shapes of half-lenses, except lateral adjustment.
These half-lens shields are not disposable, and cannot be carried in the host eyeglass case unless dismantled.
The present invention is not limited to half-lens eyeglasses, although they will function well when attached to any shape and size half-lens eyeglass.
Another example, U.S. Pat. No. 4,338,004 to G. W. Vosper on Jul. 6, 1982 discloses snap-on lenses for eyeglasses that require a groove to be placed in the nose contacting surface and the adjacent frame locations to secure resilient, flexible, colored transparent plates behind each eyeglass lens. But, this device does not shield eyesight from above and below lens, and the peripheral temporal areas are left unprotected.
In addition, this Vosper invention is not disposable, and requires permanent renovation of regular eyeglasses to accommodate installation of these shields.
Another example, U.S. Pat. No. 4,726,075 to M. T. Henrichs on Feb. 23, 1988 discloses disposable side shields for left and right sides of eyeglasses. These side shields cover the area between lens and eyes of the wearer to wind, dirt, and the like. But, no claim is made that these eye shields protect against bright sunlight and other glare, as these are made of leather, cloth, vinyl or the like; and therefore, they are not described as transparent, thus making this invention of limited relevancy to the present invention.
A disadvantage with these Henrichs"" side shields occurs when they are worn by anyone operating a moving vehicle because of restrictions created by these devices on their field of vision. There is a high probability that wearing these xe2x80x9cside-blindersxe2x80x9d will cause a vehicular accident as the result of not being able to see hazards within their normal field of vision.
Another example, U.S. Pat. No. 4,797,956 to E. L. Boyce on Jan. 17, 1989 discloses a transparent eye shield, which is used singly or in conjunction with a protective face mask. It claims to provide eye protection from small objects and harmful or contaminating fluids, which might otherwise contact eyes. This invention does not claim to shield harmful rays of the sun or other bright light, although it does describe a variation that is tinted to protect eyes from the bright flash from welder""s torches. This limited variation in protection is not claimed by the present invention, and therefore has no comparable relevancy.
It also claims to be disposable, based upon its low cost. But, since this device is used primarily in industrial, medical and academic applications, the cost of use and disposal is absorbed into those productive applications and can be defrayed within such value added processes. But, this Boyce invention cannot be considered disposable for the average wearer of eyeglasses when worn as a temporary glare shield as it bears a cost factor that cannot be ignored.
Another example, U.S. Pat. No. 4,973,148 to A. E. Gazeley on Nov. 27, 1990 discloses an optical accessory for use in combination with spectacles with an arrangement that provides a releasable attached accessory that connects such optical members in a spaced apart relationship. Although this Gazeley invention claims to be a sun shade device, it does not protect eyesight from sun light from above and below the attached device, as well as sun light at the temporal sides of eyeglasses as does the present invention.
Another example, U.S. Pat. No. 5,321, 443 to R. E. Huber on Jun. 14, 1998 discloses a removable sun glass assembly that is attached to conventional eyeglasses. Although this Huber invention shields eyesight to some degree below eyeglasses and at the sides, it does not provide this protection above eyeglasses and therefore should not claim to provide complete peripheral protection at all potential areas of sunlight. It addition, it should not claim to be generally disposable, but rather disposable at considerable cost.
Another example, U.S. Pat. No. 5,388,269 to B. P. Griffin on Feb. 14, 1995 discloses an eye shielding apparatus that substantially encloses all regions of the left and right eyeglass lenses. Claims stated in Column 7, numbers 6 and 10, describe this eye shielding apparatus as consisting of thermoplastic material, which must be assumed to be transparent although not so disclosed. Thermoplastic material can be reformed when reheated. It is thermosetting plastic than retains its shape even when reheated. The Griffin sunglass assembly would not retain its original shape if exposed to intense sunlight environments, as they are made of thermoplastic material.
Another disadvantage with the Griffin invention is that no reference is made that it is tinted or has glare protection and must therefore have no special protection against bright glare or sunlight hazards. And, since it is mounted on a pair of regular eyeglasses, it does not extend protection above, below and at the temporal sides, with the shape and size of such eyeglasses establishing the limits of protection. The shield is limited to the area of the eyeglass lens.
Another example, U.S. Pat. No. 5,394,567 to R. O. Vatterott on Mar. 7, 1995 disclosed shields for application to temple bars of eyeglasses that protect user eyes from wind, dust, and debris, with particular emphasis to such sources from above. This Vatterott device does not claim to protect eyes from bright sunlight and the like. And, it is not disposable. It should not be considered to have meaningful relevance to the present invention.
Another example, U.S. Pat. No. 5,402,189 to V. L. Gill on Mar. 28, 1995 discloses a side shield for eyeglasses and a method of making same. It includes use of a metal foil shape retentive member sandwiched between two additional layers of material that are also not transparent. These side shields are placed on the eyeglass stems next to the wearer""s temple regions and are claimed to block peripheral light and wind.
A disadvantage exists when these side shields are worn by an operator of a moving vehicle, such as an automobile, truck, boat, or aircraft, and the like, since all vision on either side is blocked by these side shields. This disadvantage is also present when wearing these side shield during times when a person is jogging or walking near highway traffic, as well as when cycling, skiing, roller-blading, or any occasion when someone finds it necessary to be aware of hazards from nearby activities. These Gill devices cause such wearers to be exposed to hazardous risks resulting from their restricted field of vision.
Another example, U.S. Pat. No. 5,502,516 to W. B. Elterman on Mar. 26, 1996 discloses a disposable/reusable sun filter, or light shield that includes a relatively thin but rigid body of light permeable material. This material is mounted directly on the outside of each eyeglass lens using an adhesive that minimizes optical interference by being placed at certain locations on the shield. It is said that the body of this shield has a thickness of between xc2xc millimeters and 4 millimeters, claiming a range of shapes, thickness and mountings on eyeglass lenses so as to provide prescription corrections. A further object of this invention is to provide for conversion of non-prescription glasses into reading or bifocal eyeglasses. The present invention claims no optical correction or conversion and should not be considered relevant to this Elterman invention.
Another example, U.S. Pat. No. 5,555,038 to S. M. Conway on Sep. 10, 1996 discloses a unitary lens for eyewear that provides improved aerodynamics, aesthetic appearance and eye protection for sportswear applications. It is claimed that this invention intercepts peripheral light for improved vision during sports activities and accomplishes this claim by the close fit to the wearer""s head.
A disadvantage develops with this claim for those who wear eyeglasses of a style and size that do not fit closely to the wearer""s head, or are overall too large to allow a close fitting Conway device. This restricts this invention to those who either do not wear eyeglasses and those who wear eyeglasses that accommodate such invention.
Another disadvantage is the difficulty of stowage of this invention. It is not disposable, and must be stored in a special protective cover of some sort. And, it is obviously more expensive than my invention and appears to be limited to those engaged in certain outdoor sports activities.
Another example, U.S. Pat. No. 5,614,963 to C. D. Parker on Mar. 25, 1997 discloses a detachable sun shield for protecting eyes from U. V. and infrared components of sunlight. One major disadvantage with this invention is that it requires modification of standard eyeglass frames in order to attach the device. And, it is not disposable, and requires a special stowage case when not in use.
Another disadvantage is that it obviously would place a disproportionate amount of weight to the front of eyeglasses and cause them to slide down the nose of wearer. This would require frequent annoying adjustment by the wearer to keep this sun shield in its proper position.
Although it is stated that these sun shields can be placed on standard prescription eyeglasses, required modifications appear to be extensive although described as xe2x80x9cslight modificationxe2x80x9d.
Another example, U.S. Pat. No. 5,617,153 to L. L. Allen et al, on Apr. 1, 1997 discloses a lens shield overlying the outer surface of eyeglass lens consisting of a thin sheet of polymer material with the xe2x80x9cmolecular structure of the eyeglass lensxe2x80x9d. It is further stated that such shields are held in place on the eyeglass lens by means of xe2x80x9cadhesionxe2x80x9d of the type that holds molecules of unlike substances together. It is assumed that Allen is describing magnetic attraction.
A problem exists in these statements, which is first identified in the statement that the polymer material has the same molecular structure as the eyeglass lens. In fact, they do not. Allen is probably trying to say that the polarity of each of these components have an attractive adhesion, meaning that they would be of opposite polarity, which does not imply they have the same molecular structure.
Secondly, he describes such adhesive force as limited to a xe2x80x9cperipheral bandxe2x80x9d, shown in FIG. 3, said to be xe2x80x9c5 mmxe2x80x9d in width. Not only are these descriptions of adhesion questionable, but there is no logical reason to limit the adhesive force to a peripheral band.
My invention has no such problem, as it employs a state-of-the-art self-adhesive material that does not cause any variation in optical characteristics of host prescription eyeglasses.
In addition, this Allen invention limits any shielding protection to the area of the host lenses. Glare and hazardous rays of the sun can reach eyesight from above and below, as well as at the temporal sides of eyeglasses. The present invention protects eyesight of the wearer at all peripheral areas above, below and at both sides.
Another example, U.S. Pat. No. 5,694,192 to S. Lucki et al. on Dec. 2, 1997 discloses a clip-on tinted lens assembly for eyeglasses. The tinted lens is described as having a xe2x80x9ccircumferentialxe2x80x9d groove, in which is placed a tension thread. Clips are mounted on the tension thread, and extend outward to engage the frame of an eyeglass in a proper position. It is said that these lens modify xe2x80x9cprescription eyeglassesxe2x80x9d to compensate for differing light conditions. But, these tinted attachments have a disadvantage since they are limited to the size of the host eyeglass frames and do not extend shielding protection above and below the front of eyeglasses, as well as providing no protection at the temporal sides. Bright glare and sunlight are not shielded at locations beyond the edge of host eyeglasses.
This Lucki invention is not disposable, and is obviously more costly than other such devices.
Another example, U.S. Pat. No. 5,694,240 to J. H. Sternbergh on Dec. 2, 1997 discloses a sunglass having a multi-layer coating on a concave rear lens surface claimed to reduce transmission of UV radiation and allowing desirable transmission of certain visible light rays. But, there is no reference given to the size, style and function of eyewear used. This invention does not extend light-shielding protection for any of the peripheral areas of eyeglasses, above, below and at the temporal sides.
Another example, U.S. Pat. No. 5,740,560 to F. J. Muoio on Apr. 21, 1998 discloses protective goggles which consist of transparent protective members made of a polarized lens for reducing glare and to provide protection against flying objects and airborne contaminants, UV radiation, and other hazards. This invention stresses protection against eye injury, but also gives emphasis to such protective members being adhered to both sides of eyeglass lens thus covering the inside of lenses. In doing so, Muoio acknowledges the likelihood of airborne hazards impacting the inside surface of eyeglass lenses. This same likelihood exists for airborne hazards that will impact eyes, since that area remains unprotected to hazards entering at both peripheral temporal sides. This is a major disadvantage that does not exist with my invention. In fact, my invention extends protection above and below eyeglass frames, and at the sides, providing a complete barrier to airborne hazards.
Rather than place additional shield film over a first layer, as is the case with this Muoio invention, only one layer is used for the present invention, which may be discarded if desired after the temporary hazard has ceased.
Another example, U.S. Pat. No. 5,764,333 to J. R. Somsel on Jun. 9, 1998 discloses a method and kit for making sunshields for eyeglasses from thin plastic sheets, and a kit which includes a special container for these sunshields.
The method of making these sunshields requires the maker to follow a process that first scribes an outline of the lenses onto a sheet of writing paper. Then they must cut this outlined design from that sheet so as to create a template with which the size and shape of the lenses can be duplicated on to a thin plastic sheet. This duplication is then cut from the plastic sheet to make the sunshield, which is said to adhere to each eyeglass lens by xe2x80x9celectromagnetic radiationxe2x80x9d. (Which is commonly called, xe2x80x9celectrostatic attractionxe2x80x9d; a method employed by other prior arts to hold a plastic sunshield to the surface of eyeglass lenses.)
A disadvantage with this method can be identified in its complicated manufacturing process, as it requires a number of steps to construct each left and right lens cover. In order to meet the requirement of a sun shield the resulting size and shape must be flawless, otherwise a breach will occur that allows bright light to enter the wearer""s eyesight. This is an even greater hazard when such light occurs by surprise, and could startle wearers of this Somsel method when operating a motor vehicle, or involved in a sports activity or the like.
In addition, it is claimed that such Somsel shields are made of a polarized plastic film of either polyethylene, polystyrene or polyester types, which commonly is known to have varied polymerization of monomers, each with varied electrostatic properties. These variations may not provide consistent reliable adhesion.
Further, the present invention uses a well proven method of self-adhesion that can be relied upon under all extreme conditions, indoors and outdoors; and does not impart any optical variance in vision as many proponents of electrostatic adhesion would like to indicate. Further, the present invention does not require being made by the wearer; and there is no possibility of breaches or gaps being created by imperfections in the pattern/ cutting process. The present invention is distributed in a xe2x80x9cready to applyxe2x80x9d packet, in a shape and size that fits all eyeglasses and supplies a continuous shield above, below and at both sides of eyeglasses. It is a simple, effective, low cost, disposable glare shield with wide applications.
Another example, U.S. Pat. No. 6,003,990 to N. Einhorn on Dec. 21, 1999 discloses a temporary lens for attachment to prescription eyeglasses by means of electrostatic force, which contains optical components in a unique combination to relieve visual problems associated with prolonged computer use.
The object of this invention is not related to those of my invention, as there are no optical components found in my device. Instead, the present invention gives emphasis upon not having any optical components that may interfere with host prescription eyeglasses.
Another example, U.S. Pat. No. 6,113,233 to R. G. Miller describes a lens cover system that includes certain tools, materials and instructions for making the same, along with a storage system. As disclosed by Somsel, this Miller invention also describes a required procedure for making this lens cover system. Certain disadvantages can be identified with the Miller device that reduce its relevancy to a negligible degree. The Miller system produces a lens cover that is limited to the same shape and size of host eyeglasses, and by doing so allows glare, sunlight and the like, including airborne hazards and contaminants to reach the wearer""s eyes from above, below and at each temporal side. The present invention does not have these disadvantages since all peripheral areas above and below the frames and at the left and right sides are completely shielded from such hazards and contaminants. One shape and size glare shield fits all shapes and sizes of eyeglasses. And, it does not require being constructed in advance, but instead is ready for immediate use when and where temporarily needed.
These difficulties, problems and disadvantages of prior art are overcome by the present invention in novel ways that are simple, inexpensive and efficient, while providing better and more advantageous results.
The present invention remedies the above described deficiencies of prior art, providing novel and improved temporary glare shields that completely protect eyesight from glare, sunlight and other forms of bright light. Such glare shields protect eyesight not only within the area of eyeglass lenses, but also throughout peripheral areas above and below eyeglass frames in the front as well as left side and right side temporal areas. Said glare shields also provide protection against airborne hazards, flying insects, contaminants and strong wind. A distinct advantage is provided by this invention is that one shape and size substantially fits all shapes and sizes of eyeglasses. These light weight glare shields do not add excessive weight to eyeglasses and do not cause them to slide down wearer""s nose. The present invention is a low cost, temporary and disposable glare shield that has particular advantages for those who are exposed to previously stated hazards as workers, spectators and participants in many outdoor activities. It has special application to those who serve in the military with particular efficiencies in distribution, use and disposal.
This present invention is easily adhered to the exterior of eyeglasses by means of clear self-adhesive that causes no optical variation and allows removal without leaving any adhesive residue. Such glare shields can be reused, and stowed in the handy packet folder provided until temporary need arises again.
Accordingly, it is a primary object of the present invention to provide a glare shield attachment to the exterior of eyeglasses that substantially protects eyesight at all areas of potential entry of sunlight, glare and other bright light, that is made of flexible tinted plastic sheet material with UV filtering properties.
It is another object of the invention to provide such glare shield at a low cost, so that it is disposable after temporary use or may be used again and again.
Another object of the invention is to provide lightweight glare shields for attachment to eyeglasses that will not cause them to slide down the nose of wearer.
A further object of the invention is to provide a simple, convenient folder packet for stowage of such glare shields before and after they are temporarily used of a size that will fit into a shirt or jacket pocket.
Yet another object of the invention is to provide the means of self-adhesion of such glare shields that does not cause any optical change in visual characteristics to host eyeglasses and does not leave any adhesive residue on lenses when shields are removed.
And, another object of the invention is to provide glare shields of a shape and size that substantially fits all shapes and sizes of eyeglasses.
Another advantage of the current invention is that it provides an effective eye shield for eye patients who have had their eyes dilated during examination by optometrists and require temporary protection against bright light, particularly sunlight, during the time their eyes are dilated. The low cost of this glare shield allows optometrists to provide their eye patients with this temporary protection as a xe2x80x9chand-out.xe2x80x9d
Another object of the present invention is to provide glare shields that also protect eyesight against airborne hazards, flying insects, contaminants and strong wind.
Still another object of the present invention is to provide temporary glare shield protection that can be conveniently distributed by venders at outdoor events or vending machines. This includes outdoor activities such as parades, sports events held in stadiums, racetracks, and wherever spectators are assembled under the sun.
Activities at the beach, golfers, hikers, automobile drivers, truckers, bus drivers, farm workers and field hands, military personnel, in fact any activity where people are outdoor participants at work or play and find temporary sun protection is needed can use this present invention to their distinct advantage.
Another advantage of the present invention is to provide glare shields that may be applied to eyeglasses in multiple layers of protection, noting that in certain extreme conditions of bright light additional glare shields may be added to other protective layers beneath. By creating a stratum of two or more layers of glare shield protection can be made to be sufficient to meet the need of any extreme sunlight situation. When such temporary extreme conditions cease, added layers of glare shield may be removed in the reverse sequence as needed, thusly maintaining a level of protection appropriate for varied conditions of bright light and airborne hazards.
A further embodiment of the invention is to provide glare shields that may be adhered directly to the face without wearing eyeglasses. In this way glare shields can be made to span the recesses of left and right eye socket areas without hindering eyelid movement, thus providing aforementioned protection to those not wearing eyeglasses. This is a particularly needed object for many that do not or can not afford the cost of eyeglasses. Many must live and work primarily out-of-doors. Such is the condition of vast populations living within equatorial latitudes of the world that spend much of the day exposed to the sun without UV protection and many airborne hazards. This embodiment should be considered within the scope and spirit of the present invention.
Another object of this latter embodiment, illustrated in FIG. 4, is to provide an eye shield that is worn by members of the military when exposed to conditions that may be injurious to eyes or may impair vision. This lightweight, disposable and inexpensive glare shield offers protection against powder-burns from nearby explosions, seals the areas surrounding eyes from airborne hazards that may include toxins and contaminants, reduces the harmful exposure to bright sunlight while deployed in positions, and provides a wide, unobstructed field of vision for better sightings of the enemy. Such glare shields may also be worn by military personnel as a protection against exposure to eyes when submerged in water that contains harmful fluids such as gasoline, hydraulic fluids, oil, and the like.
Another object of the embodiment illustrated in FIG. 4 is to provide an eyeshield that may be worn directly upon the face as shown, and under eyeglasses. This provides sealed protection for eyes, allowing eyeglasses to be also worn by those who wear temporary corrective lenses for close visual improvement and reading only.
Additional benefits and advantages of the invention will become apparent to those skilled in the art to which it pertains upon reading and understanding this detailed specification that should also be considered within the scope and spirit of the present invention.

Temporary, disposable glare shield for eyeglasses